1. Field of the Invention
This invention relates generally to die cutting operations for corrugated board or the like, and more particularly to means and the method for setting-up in-line stripping apparatus in die cutting operations with flat-bed cutting presses.
2. Description of the Prior Art:
Although there are several systems for manufacture of die cut products in paper, cardboard, and corrugated board, one of them of particular interest with reference to the present invention is a system using flat-bed die cutting presses. One brand of press is the Bobst Press. Some general illustrations of major portions of such presses are shown in U.S. Pat. Nos. 3,060,776 and 3,998,452. These illustrate stripping devices intended to strip waste pieces from a sheet of board which has been cut by a cutting die. The press is arranged so that cutting dies of various configurations can be used with it to make die cut pieces of different shapes, the shape depending upon the particular die being used in the press at any given time. For effective stripping of waste from the board, stripping apparatus matching the cutting die, must be used in the stripping station. Typically, such stripping apparatus has included at least a female stripping board or template which has ejection holes at the locations where waste is to be punched from the die cut sheet. This is mounted immediately below the plane of travel of the sheet through the press, and in line with the direction of travel of the sheets through the press. Appropriate punches are mounted to a grid or grating above the sheet path so that as the template is raised by an appropriate mechanism, the punches punch the waste from the sheet. In some of the most recent presses, the template is stationary and the punches descend to punch the waste from the sheet.
It is necessary to align the punches with the ejection holes in order to enable the punches to pass into the holes as necessary for the stripping function. This is normally done by visually aligning the punches with the template holes after the template has been secured in the press, whereupon the punches can be located and attached to the grid by appropriate clamps. Since this can be a very painstaking and time consuming procedure, resulting in considerable down-time of the press, a more convenient way has been devised which involves pre-mounting the punches or stripping blocks to a stripping board, with the board being mounted to the grid. Although this has saved some time, visual alignment has remained necessary to be sure that all of the punches are visually aligned with the corresponding ejection holes in the template. Then, after the stripping die and the template have been lined up on their respective upper and lower supports, the machine must be carefully manually jogged to close the stripper die with the template to verify that proper alignment has been achieved, and thereby avoid damage to these components or faulty stripping, once the machine is activated for a production run. This procedure, although effective to save some time by comparison with the previously described procedure, is nevertheless, somewhat time consuming and demanding of operator skill. The present invention is directed toward an improvement in terms of reduced requirements of skill and time.